If you looked toward the Santa Ana Mountains Monday, they might have appeared hazy and indistinct — the result not of smog or wildfire, but of a thick marine layer that some feel has lingered far too long.

“Typically, we have a marine layer of some type out there,” said meteorologist Mark Moede of the National Weather Service. “It’s just that in August, it starts to become a little shallower than it has been this August.”

Much longer, Moede said, and we’ll be transitioning into the Santa Ana wind season, which comes as early as late August but typically in September or October. The warm winds blowing out of the mountains can greatly increase wildfire danger.

The lingering low-pressure could well be a result of another transition: between El Niño, a periodic warming of equatorial Pacific waters, to La Niña, a periodic cooling, which is happening right now.

Climatologist Jan Curtis of the Natural Resources Conservation Service in Oregon traced the statistics backward, and discovered the pattern. In years when El Niño was making the transition into La Niña, the low-pressure “trough” along the West Coast lingered longer than normal as well.

El Niño can mean increased winter rains for Southern California, while La Niña can bring dry conditions, though it is too soon to tell how this winter’s rains will turn out.

The cool temperatures, meanwhile, might soon be shifting.

This week’s forecast calls for clouds in the morning, sunny skies in the afternoons, with a gradual warming toward the weekend that could raise inland temperatures as high as 91 Saturday and Sunday.